<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Title</title>
</head>
<body>

</body>
<script>
	function fn1() {
		console.log(1);
	}
	function fn2() {
		console.log(2);
	}
	fn1.call(fn2);// 1
	// 运行call,并将call函数中的this指向为fn2
	fn1.call.call(fn2);// 2
</script>
</html>